1. Field of the Disclosure
The present invention relates to laser display systems, and more particularly to device and method for adjusting white balance in a laser display system, which enables to adjust white balance taking an optical characteristic of a laser beam into account.
2. Discussion of the Related Art
In general, the laser display system, such as a laser projector and a laser projection, for showing a picture by projecting an image signal onto a screen by using a laser beam from a laser beam source, is used for having presentation in a meeting room, and as a projector in a theater, a domestic home theater, and so on, mostly.
The laser display system uses red, green, and blue laser diode as the laser beam sources.
The laser diode used as the laser beam source can adjust laser beam output intensity with a current applied thereto.
In general, the laser diode has intensity of the current at which the laser beam output intensity increases sharply, called as a threshold current Ith, and starts oscillation at a current level exceeding the threshold current Ith.
However, the laser diode is liable to have the laser beam output intensity variable with a temperature characteristic of the laser diode.
That is, even if the same current is applied to the laser diode, the laser beam output intensity of the laser diode can vary with temperatures.
FIG. 1 illustrates a graph showing a relation of a temperature versus variation of laser beam output intensity of a laser diode, wherein it can be known that a functional relation between the laser beam output intensity and the current increases or decreases with the temperatures.
For an example, if the present temperature changes from 25° C. to 40° C., the laser beam output intensity of the laser diode changes from P1 to P2 even if the same intensity of current is applied to the laser diode.
If the laser beam output intensity varies thus, proper white balance of the image being displayed can not be provided, causing a serious problem of providing an image of poor picture quality to a user.
Consequently, development of a system which can adjusts the white balance is required taking the characteristic of the laser diode into account in the future.